we had a lot of theories, we had a lot of science that suggests what the causes may be. but in reality, we don't know for sure. >> reporter: as for cervical cancer, considered by many to be a medical success story due to effective screening methods and early detection, new cases are down, but other hpd related cancers are up, including oral cancers in men and women. >> women in this country are so fortunate to have pap smears readily available to us. hopefully as our medical community moves forward, we'll look toward applying these types of screening techniques toward other types of cancers related to hpv. >> reporter: cancer experts say there is no uniform test for oral hpv, so screening is not routine. dr. powell tells her patients' parents, the hpv vaccine is a critical tool in fighting cancer. the cdc recommends all men and women into their 20s get the hpv vaccine. three doses over the course of at least six months. but for the vaccine to have the greatest benefit, the cdc recommends vaccinating both boys and girls beginning at ages 11 and 12. why so early? the vacci